Method of making insulating elements



'C. H. IHORDAHSON.

METHOD OF MAKING INSULATING ELEMENTS.

APPLICATION FILED MAR. 20. i915.

Patented Feb. 3,1920.

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APPLICATION FILED MAR. 20' I915.

Patented Feb. 3,1920. I v 4 SHEETS-SHEET 2.

C. H. THORDARSON.

METHOD OF MAKING INSULATING ELEMENTS. APPLICATION FILED MAR. 20. I915.

1 ,329,81 5. v Patented Feb. 3, 1920.-

4 SHEETS-SHEET 3.

7/ K/IW 'llllll/ v C. H. THORDARSON.

METHOD OF MAKING INSULATING ELEMENTS.

APPLICATION FILED MAR. 20, 1915.

4 SHEETS-SHEET 4- 1,329,815. Patented Feb. 3,1920.

UNITED STATES PATENT oFF cE.

CHESTER THORDARSON, OF CHICAGO, ILLINOIS.

METHOD OF MAKING INSULATING ELEMENTS.

Specification of Letters Patent.

Patented Feb. 3, 1920.

Application filed March 20, 1915. Serial No. 15,929.

To all whom it may concern:

.Be it known that I, CHESTER H. THORDAR- SON, a citizen of the United States, and a. resident of Chicago, in the county of Cook and State of Illinois, have inventedcertain new and useful Improvements in Methods of Making Insulating Elements; and I do .hereby declare that the following is a full, clear, and exact description'thereof, reference being had to the accompanying drawings, and to the characters of reference.

marked thereon, which form a part of this specification.

This invention relates to a novel method of making insulating elements composed of a plurality of superposed turns or sheets of insulatin with a owable insulating medium during the winding or laying on operation; Said insulating element may have the form of a tube to surround the magnetic circuit of an electromagnetic device, as a. transformer, or may be-of flat form for general insulating uses.

art, in winding a sheet of suitable fibrous Insulating material, as paper, into a tube in the presence of a high vacuum, the sheet of -material being impregnated with a fluid insulating medium which subsequently hardens and which constitutes also a thin filmbetween contiguous convolutions of the rolled sheet. The high vacuum has the effect of drawing the air and gases from the body of the sheet material and from the insulating compound, which avoids the formation of bubbles in the walls of the tubes,

thereby increasing the density and hardness of the resultant product.

As an additional means for driving the moisture and other foreign matter from the insulatiilg sheet )rior to the winding operation, I may su ject said sheet just before it is wound into the tube to the influence of an clcctro-static field produced between an material which are impregnated The method herein described is an improvement on the method dlsclosed 1n elongated electrode included in a high potential circuit and a similar electrode included in' a portion of the machine which is grounded. Conveniently one of the electrodes may consist of a metal roller about which the sheet is guided to the forming tube between the insulating bath and the forming tube.

When the insulating element assumes the form of a flat sheet it may be made by slit ting or dividin fore the insulatmg compound has hardened, and thereafter flattening the tube or sheet and applying pressure to press the'layers together when the insulating compound harens.

In the drawin s': A Figure 1 is a l rorizonta'l sectional viewof a convenient form of machine for practising my novel-method; I

Fig.2 is a transverse. section thereof. Fig.3 is an enlarged'detail of the laying on or ironing roller and the .eIectrO-static electrodes.

Fig. 4 is a diagrammatic perspective of the tubethus formed be- Fig. 7 is a diagrammatic -'view showing a: at

method of producing a flat form of insu ing element.

The tube winding mechanism is a power drivenself contained machine which islocated Within an air tight tank 10 which has connections through a suitable hose or pipe fixed frame, consisting of rigidly connected upright and horizontal members 14, 15, respectively, of any suitable design, which is provided with wheels or rollers 16 which travel on tracks 17', 17 withinthe lower part of the tank 10. Said tank 10 is preferably circular in cross section and isprovided at one end with a fixed wall 18 and at its other end with a removable wall 19. When said movable wall 19 is removed said winding mechanism may be run outwardly from said tank onto an extension track 20, indicated in Fig. 1, arranged in line with the tank rails 17 so that free access may be had to the winding mechanism to remove a wound tube therefrom or to replace the paper or other... sheet roll thereon from which the tube isv wound.

The tube may be wound upon a 's'uia able mandrel 25 which may be made like the collapsible mandrel shown in my aforesaid prior patent,the shaft .26 of said mandrel the insulating being mounted in bearings 2-7 supported on the winding. mechanism frameflQ-S desige nates a rotative reel mounted in. said frame which receives a roll of sheet material that};

is unwound therefrom to produce theinsu-I lating tube. The sheet a is carried from the reel over a guide, roller 29 rotatively mount; ed at the topfofthe frame, thencedown wardly into a;.-receptacle 30 which contains compound in-liquid state, he-

ing guided by rollers 31, 32' within, said retube. Thebearingsfor the roller35- are our r-ied by the upper ends of insulators 35'. At the line at which the sheet is laid on said mandrel or the forming tube. there is provided an ironing or ressing roller 36 which presses the sheet close yupon the formingtube I in a manner similar to the like ironing roller shown in my aforesaid 'prior'appllcation.

The mandrel 25 may be rotated by an electric motor 38 throughthe medium of a worm and Worm wheeldrive 39. A suitable tension device may be applied to the roll supporting reel or to the roll itself to' prevent a too free unwinding of the sheet material from the roll. One form of tension'device suitable for-the purpose is shown in" my aforesaid prior patent. K II y The ironin roller36 is 'mounted in the I upper ends -0 swinging arms 42, oneat each end of the machine, and which are pivoted at their lower ends to the frame and swingat their upper ends toward and from the mandrel. The said roller 36 is pressed toward the is herein shown as effected by means of the as harpened edges of upper and lower scraper forming tube b a spring pressure, which may be effected y means of springset t each attached at one end to'the swinging le vers 42 and-connected at their other ends by llIlkS '45 to hand levers 46 which are pivoted, at 3 their lower ends to the frame and are adapt -ed to be locked attheir upper ends to su1table racks 47. The hand levers 46 provide means whereby the spring pressure of the roller 36 against the forming tube may be varied.

Between the rollers 32 and 35 the sheet is subjected to a scraping operation for the ur'pose of removing surplus insulating ma terial therefrom. I Such scraping operation ,bars 48 49, respectively, which are attached at their ends to and extend between. the swinging roller bearing" arms 42. I The said scraper bars, as herein shown, have the form of angle bars and one edge-of each bar is sharpened to constitute'ia scraping edge. As

Therein shown, the vertical member of the lower bar is sharpened at its lower edge and the sheet passes upw-ardly thereacross and along the flat. face'of-the bar to scrape the excess material theouterface of the sheet, and the inner face vof the sheet is brought to bear against" a sharpened scrapin edge formed 'on'the horizontal member 0 the up er bar 48 I :Pre erabl the guide roller 32 and the scraper bars. 48, 49 are: provided with suit-,

able relatively low resistance heating ele ments, 50, 52, 51', respectively, which are connectedwith a suitable source of relatively low pressure current so that said roller and.

bars may be kept suitably heated so as to prevent the congealing 0f the liquid insu- Iating medium on the surface of the-sheet before it is scraped therefrom as itemerges from the insulating bath. Said resistance or heating elements of. the scraper'bars and roller are shown as connected in multiple to a supply line at the plug 55 and the feed side of the circuit is provided with a switch 56 by which current tothe heating elements is controlled. The insulating medlum in the tank may be maintained, in a. fluid state by any suitable application of heat as, for instance, by the use of burner pipes 57.. Preferably also the tank may-be provided with one -or more internal heating elements, 58,

one being herein shown as located near the' rising-side of the sheet a to assist in maintaining the insulating medium in a'suitably fluid condition for application to the sheet.

These heating elements need be only of com.-

paratively low heating power The heating elements of the scraper bars may be insulated' from the bars by being wrapped in .covers of a. suitable insulating material, as asbestos. They prevent the scraper bars from chilling the coating on the paper so that, thereby the said insulatin medium may be kept sufliciently fluid toe readily removedor scraped therefrom. The resist: 'ance or heating element 58 is also incl'osed in an insulating cover and it is connected also to'the' plug 55 and is'provided with an independent switch 59 whereby the control of the current to the said heating'element 58 may be independent of the control of the current to the scraper bar and roller heating elements.

The motor 38 is fed from a supply plug 60, and the motor circuit is provided with the usual regulator 61 and with a cut-out switch62 To the feed side of the motor connected a series of lamps (it shown in Fig; 2 as supported while it issubjected to the'drying influence of a fan. or other suitable drying means-{1 I I p 't k nd the. end wall,1 9 is fastened.

peration off-wind r20 I asaa eis is a shearing .device for cutting the sheet which is bemg: wound after the desired number of turns have beenwound into the.

tube. The shearing device herein diagrammatically shown consists of a fixed blade 67 and a swinging blade 68, both supported in any suitable manner on the swing bars 42. Normally the blades are separated, as

.- a source of high tension pulsating direct indicated in Figs-3 and 4, and the paper after its emergence from the insulating' bath passes upwardly between the shear-.

ing blades, The swinging blade is held in its I open position by means of alatch 69 which is providedwith .a tooth to engage a pin I The latch 70 on the said swinging blade. is provided'at one end with an armature 71 whichco-acts withthe core ofa trip- 3 ping coil 72, one side of the .energizing; circuit of which, asherein shown, is connect; ;ed to the feed side of themotor circuit,'the- I other side being connected to the return' The said tripping coil; circuit is provided; with a} switch 73 which,v when closed, completes,

upibetween the said electrode or roller 35 and: the said grounded.;metallic portion of side of the said motor circuit.

the circuit through the coil and energizes the same to tripi'the latch 69and permit the swinging blade to be moved toward thew. .fixed blade under the influence of a -shearing spring 7 5, to thereby sever the sheet. I I I After the sheet has been severed by the shearing device'the end wall 19 ofthe tank 1'0 is removed Landgthe winding and sheet insulating 1nechanism'--is: drawn outwardly onto external. tracks whiCh are fitted in end to end relation to the tank tracks 17 The connection of the various circuit wires to the internal terminals is 'such'as to permit the mechanism to 'b'e thus'drawn outwardly from the casing 10 without dis'connecting the circuit. I

In order to prevent air leaking into {the spaces between .the* convolutions orturns" of the wound tubegatthe ends thereof-after its withdrawalfroin' the tank' or casing 11),

the rotation of the finished tube is continu'ed f, I I

*mandrel, and thereafter the mechanism thus-equipped is pushed into the casing Theapplic'ation of heat is contlnuedlto 'the,

insulating medium to maintain it in a; liquid] I state." Thus the liquid insulatingmedium seals the interspaces between theconvolu-. tions or turns of the tube and prevents leak age of air therebetween'. 5-

After the tube has been sufiiciently cooled the winding mandrel and the said tube are removed from the frame,xand the winding mandrel removed from the tu'be. The tube may, if desired, be SlllHGCtetltQ an exterior pressure in the manner "indicated in my aforesaid patent to prevent the separation Y ifthe final insulatin in a new tube is begun.

second treatment of the insulatin ,.It will be understood, of course, that the tube may be wound on a cylindric mandrel in which event the exterior pressu'reyvill not usually be a plied during the setting or hardening of thetube is removed om the mandrel prior to the setting or hardening operation and the tube. As before stated element is to be fiat,

issplit and flattened and subjected to pres-' sure while being dried or set.

The roller or electrode 35 is connected to current through the means of a conductor '7 7 said conductor being insulated from the tank 10 by a suitable insula'tor 78; The

conductor 77 isattachedto one end of the metal rollerlbr' electrode 35 and-the circuit is open atthe other'en'd of'the electrode.

. The .upper endspfthe swinging arms 42 are I turned inwardly; and downwardly to pass I over the upper edges of "the' end walls of thefinsulatmg'ibathreceptacle; the ironing I tl e-f,frame, iIs grounded so that there is set the frame an electrostatic discharge which thicknesses of; the insulating medium, be-

tween the layers or convolutions thereof, and ,the resultant tube is also free from globules of water and-air both in the body of the sheet and between'the." convolutions or layers thereof. Thus the tube produced possesses uniform insulating qualities throughout its a'rea to a maximum de ee. 1 iAfter' the tube and t e mandrel have been removed from the 'frame,-I another mandrel orthefisame-mandrel is applied thereto, an}

'- other rollofpaper is applled to. the reel 28 and isiattached at. itselea'ding edge to the thereto, whereupon the p I referably the tank is provided wh ch or a numberof windows" 80 through-which Y has the effect ot/driving. the 'moisture from :f t-he sheet thathas just passedbetween the {scraper bars 1 In; this manner the sheet, I i while being thoroughly impregnated with --theinsulating mediumgis free from varying the tube winding operation-may be observed I from the exterior or thetank. I

In some cases I find 't advantageous to subject the sheet of insulating'material to 8;.

oundand ata tem erature lower t an the shown in Fig. 6, but permitting the sheet toto perfectly impregnate the insulating sheet withan insulating compound, such for in stance as parafiin, it is necessar to heat the compound to a substantially high temperature, in the neighborhood of 300 degrees Fahrenheit. It has been found in some cases that this temperature produces a vapor which tends to cling in a thinfilm to the-sur- .face of. the sheet and such films of vapor,

even though they be very thin, are such that in the completed tube the structure is more.

' or less loose and not so dense as is necessitated by the insulating requirements. In. order to overcome this defect, where found,

I may subject the initially treated sheet to a I second treatment in an'insulating com ound bath under alower temperature than t e initial bath as, for instance, in the neighborhood of-180 to 200 degrees Fahrenheit when Winding the final tube. Whenthis practice is followed the initially treated sheet may be wound on a roll or mandrel85 in the high temperature bath in the same machine or apparatus in which the final tube is wound and the sheet is thereafter unrolled from the initial tube-before the insulating compound has set or hardened and passed through the lower temperature bath 87 and wound into the final "tube on the mandrel 25, as shown in Fig. 5. M I

The same'result may-besecured by thus passing thesheet successivelfthrough an initial high temperature bath 90 and a second lower; temperature bath '91 without winding the sheet between said baths, as

pass directly from the high temperature to the low temperature bath and cooling it in transit therebetween, if found necessary.

When it is desired to produce a fiat sheet,'

the tube may be slitted longitudinally as indicated at small 6 in Fig. and-is spread flat to produce the sheet (3., The sheet is commethod of producing insulating elements is merely .one example of a number which may be'employed, and it is furthermore-understood that the illustration of said mechanism is largely diagrammatic in its nature.

I claim-as my invention:-

'1. The method of making insulating elements which consists in assembling a sheet of insulating material into a laminated ele- 1 ment assing the sheet through and impregnating the same immediately at the assembling operation with a heatedbath of liquid insulating compound which hardens as it cools, thereafter allowing the product to cool, and applying pressure symmetrically to opposite s des of the element to press the superposed layers together during the cooling of the insulating compound.

2. The method of making insulating elements which consists in winding a sheet of insulating material upon a form partially submerged in a heated bath of insulating compound which hardens when cooled, and

thereafter allowing theresultant product to cool.

3. The method of making insulating elements which consists in winding a sheet of insulating material upon a collapsibleform partly submerged in a' heated insulating medium, allowing the product to cool while under pressure to press the layers together and thereafter collapsing and removing the form. a

4. The method of making insulating elements which consists in' winding asheet of insulating material upon a form partly submerged m a heated insulating compound and thereafter allowing the product to cool under pressure greater than under which it was. wound.

5. The method of forming an insulating element which consists in rolling a sheet of insulating material into a tube against a tension exerted on the sheet while the tube is partially submerged in a melted insulatin'g compound and afterward allowing the resultant product to cool.

"6. The method of 'making insulating elements which consists in impregnatlng a sheet with insulation, winding the sheet material upon aform immediately adjacent to its reception of insulation, excluding air and water from the sheet immediately adjacent to the line on whichit passes u on theifo'rm, and thereafter removin the orm.

7 The method of .ma ring insulating elements which consists in passing a sheet through an insulating bath, winding the sheet upon a form which rotates partially submerged in said bath, excluding air and water from the sheet immediately adjacent to the line on which it passes upon the form,

thereafter allowing the resultant shell to cool while under pressure greater than that under which it was formed, and thereafter removing the form. p i 8. The method of forming an insulating element which consists in rolling a sheet of insulating material into a tube 1n the pres ence of a melted insulating compound, afterwardlongitudinally slitting the tube and spreading it flat and allowing the flattened body to cool under pressure.

9. The method of making insulating elementswhich consists in Winding a sheet of insulating material to produce a'hollow roll int-he presence of aheated bath of insulating compound which hardens when cooled,- whereby the sheet becomes impregnated with the insulating medium, longitudinally slitting the hollow roll and flattening the same and thereafter allowing the product to cool when subjected to pressure to force the layers together.

10. The method ofmaking an insulating element which consists of assembling upon each other layers of an insulating material impregnated with an insulating compound, and subjecting all parts of the layerto the influence of a high, continuous vacuum before impregnation, and thereafter allowing the product to harden.

11. The method of making an insulating element which consists in winding a sheet or" insulating material into a roll in a contir-ious vacuum, impregnating the sheet before winding with an insulating compound and thereafter allowing the product to harden. 7

12. The method of making an insulating element which consists in winding a sheet of insulating material into a roll in a continuous vacuum, impregnating the sheet before winding with an insulating compound, scraping the surplus of insulating material from the sheet before winding and thereafter allowing the product to cool.

13. The method of making an insulating element which consists in superimposing upon each other layers of insulating material impregnated with an insulating compound in the presence of a high vacuum, subjecting the sheet to the action of an electro-static discharge and thereafter allowing the product to harden.

14. The method of making an insulating element which consists in superimposing upon each other the layers of insulating material impregnated with an insulating compound and subjecting the sheet to an electrostatic discharge.

15. The method of making an insulatin element which consists in winding a sheet of insulating material into-a tube on a rotating member in a heated bath of insulating material, thereafter cutting the sheet, thereafter cooling the formed tube and at the same time continuing the rotation of the tube in-the bath to prevent the entrance of air between the overlying layers at the end of the resultant product.

16. The method of making an insulating element which consists in winding in a high vacuum a sheet of insulating material into a tube in a heated bath of insulating mate rial, thereafter releasin the vacuum and thereafter continuing t e rotation of the tube in the bath while cooling the tube.

17. The method of forming an insulating element which consists in rolling a sheet of insulating material into a tube in the presence of a liquid insulating compound under a forming pressure which edects a tight Wmdmg of the sheet and in the presence of a continuous vacuum and thereafterallowing the compound to harden under atmospheric pressure.

18. The method offorming an insulatin ing pressure which eflfects a tight winding of the sheet and in the presence of a vacuum, thereafter releasing the "vacuum while continuing the rotation of the tube in the insulating compound under the form'- ing pressure and sub ecting the sheet to the action of an electro-static discharge preliminary to its winding operation.

20. The method of making an insulating of insulating material into a roll in. the presence of a heated bath of insulating compound to impregnate said sheet and thereafter rewinding said impregnated sheet into a tube.

21. The method of making an insulating element which consists in winding a sheet of insulating material into a rollin the presence of a heated bath of insulating.

compound to impregnate said sheet and thereafter rewinding said impregnated sheet into a tube in the presence oi? a vacuum. Y

22. The method of making an lnsmating element which conslsts 1n winding 2. sheet of insulating material into a roll in the'j presence of a heated bath of insulating compound to impregnate said sheet and thereafter'rewinding said sheet into a tube and subjecting said sheet as it is wound upon the tube to the influence of an electrostatic discharge. r

23. The method of making an insulating element which consists of winding a sheet (if insulating material into a roll in the presence of a heated bathi' of insulatingcompound to impregnate said sheet and thereafter rewinding said sheet into-a tube in the presence of a heated element which consists in rolling a sheet or element which consists in winding a sheet I 12o impregnated bath of insulating material of less temperature than the original bath. j

24:. The method of. making insulating elements which consists in subjecting a sheet of insulating material successively to two baths of insulating compound of prosheet thus impregnated into a laminated insulating element, and thereafter allowing the insulating element/to set. or harden.

sheet of insulating material successively to two baths of insulating'compound of different temperatures to impregnate the vsheet, thereafter forming the sheetthus impregnated into a laminated insulating element in the presence of a vacuum, and" -'thereafter allowing the insulatingfe'lement to set or harden.

26. The method of .making?, insulating elements which consists in '-1 subjecting a sheet of insulating material successively to two baths of insulating compound of progressively decreasing temperatures to impregnate the-sheet, thereafter forming the sheet thus impregnated into a laminated in'" su'l'ating element in the presence of a v vacuum, thereafter'releasing the vacuum,

andther'eafter allowing the insulating element'. to setlor harden in the presence of said bath.-

27. The method of making an insulating element which consistsin assembling upon each other successive layers of an insulating material, impregnating the material with an insulating compound prior to the assembling of the layers and subjecting the material prior to its impregnation to a continuous vacuum during the assembling operation.

28.,The method of making an insulating element which consists in assembling upon each other successive layers of an insulating material, impregnating the material with aninsul-ating compound prior to the assembling of the layers and subjecting both the'formed element and the insulating material prior to its impregnation to a continuous vacuum during the assembling operation.

In testimony, that I. claim the foregoing as my invention I affix my signature in the presenceof two witnesses, this 26th day of February, A. D. 1915,

' CHESTER H. THORDARSON.

Witnesses:

W. L. HALL, G; E. vDowns. 

